According to the release, this could result in worker exposures that exceed agency guidelines, which are based on various health effects such as cancer.

"Manufacturers face an unexpected worker exposure issue: Workers using just one or two shop towels a day may be exposed to elevated levels of heavy metals, compared to health-based exposure guidelines," said Barbara Beck, principal at Gradient, who has testified before the U.S. Congress on lead toxicology issues.

"Without knowing it, manufacturing workers may be ingesting certain heavy metals at elevated levels from this unexpected source. For some of these metals, the amounts ingested may be greater than allowed in drinking water on a daily basis. Because towels are used and then laundered multiple times and are often delivered to different companies each time, workers may even be exposed to metals that do not otherwise exist in their work environment," Beck added.